1. Field of the Invention
The present invention relates to a nucleic acid analysis device and a nucleic acid analyzer using the same.
2. Description of the Related Art
There is a new development in a technique as a nucleic acid analysis device for determining DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) sequences.
A method utilizing electrophoresis, which is now in general use, involves preparing beforehand a cDNA (complementary DNA) fragment sample synthesized through a reverse transcription reaction of a DNA fragment or an RNA sample for sequence determination; executing a dideoxy chain termination reaction by well-known Sanger's sequencing method; thereafter performing electrophoresis for the sample; and making a measurement on a pattern of separation and development of molecular weight to analyze the pattern.
In contrast to this, there has recently been proposed a method in which immobilization of DNA or the like on a substrate takes place for DNA sequence determination, as disclosed in P.N.A.S. 2003, Vol. 100, pp. 3960-3964. The method involves trapping fragments of sample DNA to be analyzed, molecule by molecule, on the surface of the substrate in a random manner; elongating the sample DNA on substantially a base-by-base basis; and detecting the result through fluorometry, thereby effecting the sequence determination. Specifically, the nucleotide sequence determination for the sample DNA is accomplished by repeating a cycle including: a step of effecting the occurrence of a DNA polymerase chain reaction, using four types of derivatives (MdNTP) of dNTP (deoxyribonucleotide triphosphate) as a substrate of DNA polymerase, in which the MdNTP can be captured in template DNA to stop its DNA chain elongation reaction by the presence of a protecting group and moreover in which the MdNTP has a detectable label; subsequently a step of detecting the captured MdNTP by its fluorescence or the like; and a step of restoring the MdNTP to its elongation-capable state. Since this technique makes it possible to determine the sequence for the DNA fragments molecule by molecule, many fragments can be analyzed at a time, and hence an increase in analysis throughput is achieved. Also, this method can possibly be capable of the nucleotide sequence determination for each of single DNA molecules and thus be capable of eliminating the need for purification or amplification of the sample DNA, using cloning, PCR (polymerase chain reaction), or the like. Since the purification or amplification has been a problem involved in the prior art, the method can be expected to achieve a speedup in genome analysis or gene diagnosis.